[!TIP] Patient (esp. Female) with abdominal pain + neuropsychiatric features -> need to consider acute porphyria.
Clinical features: Abdominal pain, neuropsychiatric features, seizures and fever.
Can be precipitated by anaesthetic drugs and luteal phase of the menstrual cycle.
Anaesthesia for suspected acute abdomen can be catastrophic.
The defective enzyme in acute intermittent porphyria is porphobilinogen deaminase.
The defect is in uroporphyrinogen decarboxylase.
80% of cases are acquired / sporadic; 20% are inherited.
Uroporphyrinogen decarboxylase converts uroporphyrinogen III into coproporphyrinogen III.
Presents with photosensitive blistering rash.
Hypertrichosis and hyperpigmentation may be present.
Liver disease is a common comorbidity:
Triggers for attacks are caused by increased hepatic iron load but also alcohol, smoking, estrogens, hepatitis C or HIV.
Phlebotomy - used to decrease the iron load.
Hydroxycholorquine - increase the excretion of porphyrins.
1. Overnight 1mg dexamethasone suppression test
Psoriatic arthritis is associated with HLA-B27.
Differentiation is clinically important because prognosis and management are different.
| PsA | RA |
|---|---|
| better prognosis | Somewhat worse |
| Early disease -> NSAIDS | DMARDs started early |
| Dactylitis, enthesistis, tenosynovitis | - |
| pattern: asymmetric oligo / symmetric, DIP is specific | Symmetric polyarthritis of PIP / MCP |
| Sacroiliitis | - |
| Nail changes | - |
| - | proximal hand and foot involvement (?wrist and ankles) |
| Source |
HMG-CoA reductase: Rate limiting enzyme in cholesterol sythesis : found in the liver and ? other tissues
LCAT : the enzyme synthesized by the liver and attached to HDL which exterifies cholesterol so that it becomes trapped inside HDL. Required for reverse transport of cholesterol.
LPL: lipoprotein lipase: the enzyme found on tissues which removes lipids from VLDL and it's derivatives, increasing their density.
If there is acidosis (pH < 7.2 or HCO3 < 15) or high ketonemia, manage as DKA.
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+ it is **non pruritic**, starts on the abdomen and **spreads *outwards***. (Spares palms and soles)
Trombiculid mite = 'harvest' mite
Endemic typhus serves as the prototype for pathogenesis:
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[!INFO] DCT physiology
- Reabsorbs 5% of the filtered potassium.
- Contains thiazide sensitive Na/Cl co-transporter.
- Also contains TRPV-5 for calcium reabsorption.
Inheritance: #autosomal-Recessive
These changes (except the lack of hyponatremia) are very similar to changes caused by chronic thiazide use.
8. Endocrine: reduced testosterone (due to Leydig cell dysfunction) [Source](https://emedicine.medscape.com/article/120858-overview)
| Dermatologic condition | Associated |
|---|---|
| Hyperkeratotic and proliferative dermatoses | - |
| [[2022 General Medicine Paper-May#Acanthosis nigricans]] | |
| Florid cutaneous papillomatosis (rapid eruption of warts) | Stomach cancer |
| Sign of Leser-Trelat (rapid appearance of seborrheic keratoses) | Gastrointestinal adenocarcinoma AND many others |
| Tripe palm (velvety thickening of palmar skin) | Gastric or lung cancer |
| Icthyosis | Hodgkin's lymphoma |
| Palmoplantar keratoderma | Associated with SQC of oesophagus = Howel-Evans Xn |
| Bazex Xn: psoriatic like plaques on fingers and toes (acrokeratosis paraneoplastica | SQC of aerodigestive tract |
| Inflammatory dermatoses - erythematous or violaceous skin eruptions | |
| Sweet syndnrome (dermal,non vasculitic neutrophil infiltration with fever + neutrophilia) | Acute myeloid leukemia, lymphoma |
| Dermatomyositis | Ovarian, breast, cervical,uterine + others |
| Erythroderma (usually caused by psoriasis or atopic dermatitis) | Cutaneous T cell lymphoma |
| Erythroderma gyratum repens | Bronchogenic carcinoma |
| Pancreatic panniculitis | Pancreatic cancer |
| paraneoplastic pemphigus (PAMS) | Non-hodgkin lymphoma, CLL |
| Mucous Membrane pemphigoid | Unspecified but associated with malignancy |
| - | |
| Hyperpigmentation | |
| Hyperpigmentation in ectopic ACTH poduction (ectopic cushing's syndrome) | Small cell lung CA |
| ( POMC produced by the tumour is a precursor of ACTH and MSH ) | |
| Generalized dermal melanosis | Extensive metastatic melanoma |
| Skin manifestations of amyloidosis [[2022-November#Amyloidosis]] | plasma cell dyscrasias such as multiple myeloma, and less frequently, Waldenström macroglobulinemia |
Interface hepatitis is seen, just like autoimmune hepatitis.
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Symptoms : N/V, headache,
motor effects: nystagmus, tremor, cerebellar ataxia.
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Despite prominent anticholinergic toxicity in some, physostigmine is contraindicated (incr. risk of arrest)
#2023GM-NOV/Q30
Pathological causes
Drugs: